YCSB, build tools, workload files, scripts, etc. for doing testing.

Small wrapper around YCSB load driver that makes it easier to use.

• uses our patched YCSB driver that conforms to best practices for mongodb and uses our latest driver
• breaks workload definitions into "dataset" files which define the number of documents and insertorder vs. "workload" files which define the mix of read/write/update operations
• moved commonly changed attributes into a config file so it's easy to use the same settings across a number of tests
• organize workload output so it's easy to remember what settings were used
• added common presplit scripts that prepare the database for various sharded setups

• git clone this repo onto your computer
• edit the "config" file to match the settings you want to use
• ./bin/load to load your dataset into the target database
• ./bin/run to execute the workloads, saving output into the "output" directory